Getting the bright idea to text ex-girl/boyfriends, parents, siblings and enemies expecting them to enjoy your thoughts while intoxicated. This especially occurs after a game of beer pong or round of shots, during a lonely cigarette at or around 4am

"I cam this close to a TUI last night, good thing my mom doesn't know how to text!"

Typing Under the Influence, most commonly resulting in messages that should never have been sent in the first place. Commonly causing Facebook posts that make little or no sense to anyone but the person writing them.

I had to log off Facebook before I committed a TUI post to my profile.